This invention relates to absorbent products and particularly to such products which are to be worn by a user against the body and are designed to absorb body exudates, e.g., diapers, sanitary napkins, catamenial tampons and the like.
These products generally comprise an absorbent element such as a pad or core of absorbent material, optionally enveloped by a cover which is pervious to body exudate at least on the side in contact with the body. Frequently, as is the case with disposable diapers and some sanitary napkins, the side worn away from the body is provided with a barrier sheet, i.e., a sheet of material impervious to body fluid, to protect the garments of the wearer. This barrier sheet may form a part of the cover enveloping the absorbent material or may underlie such a cover on the side away from the body.
In the main, such products have performed their primary function, i.e., they have absorbed and retained body fluid. A major drawback associated with such products, however, is that after the user has worn them for a period of time, the products may fail before they become fully saturated by having fluid strike through onto an external surface contacting the user's garment or by having the surface worn against the body become so wet with fluid that the resulting discomfort causes the user to discard the product. Accordingly, there is a need for an absorbent product which makes full use of the absorbent material provided and keeps absorbed fluid away from the external surfaces of the product.
One attempt to solve this problem is described in U.S. Pat. No. 3,017,304 and 3,612,055 wherein a skin is provided on the side of the product worn away from the body and is designed to draw liquid away from the body facing side. Unfortunately, this skin has little fluid retention capacity per se and soon becomes saturated and ineffective. In U.S. Pat. No. 4,047,531 a layered structure comprising juxtapositioned layers of relatively hydrophobic and hydrophilic wood pulp are used in an effort to solve the problem. Unfortunately, the use of relatively hydrophobic material tends to decrease the overall capacity of the absorbent product and hence does not represent a satisfactory solution. The need for an absorbent product capable of absorbing as much fluid or more than conventional products but which will keep absorbed fluid away from the external surfaces of the product has, heretofore, gone unsatisfied.